With the rapid development of display technology, touch screen panels have gradually spread throughout people's lives. At present, the touch screen panels can be classified into “add on mode touch panel”, “on cell touch panel”, and “in cell touch panel” in terms of structure. The add on mode touch panel is a display panel having touch function whose touch module and display screen are produced separately and then adhered to each other.
Most of the current touch screen panels are only able to detect based on two-dimensional coordinates, i.e. being able to detect the touch position of a finger in the xy coordinates on the surface of the touch screen panel, while being unable to detect the pressure in the z direction perpendicular to the surface of the touch screen panel when the finger presses the screen.